McLaren says it has work to do overnight ahead of qualifying for the Bahrain Grand Prix as the smallest of margins could be the difference between seventh on the grid and going out in Q2.
Fernando Alonso says his aim for Saturday is to make it through to Q3 – something the team failed to achieve in Australia with Alonso 11th and team-mate Stoffel Vandoorne 12th.
The Spaniard knows it will take a "perfect" lap to achieve that given just how close the midfield pack is.
"There is a lot of analysis that we need to do concerning some of the new parts we have on our two cars, so I think we need to put everything together now and find the best compromise for tomorrow," said Alonso.
"Our aim for qualifying is to be in Q3 and we need to deliver and do a perfect lap, so that we can beat some of the cars in front of us."
Racing director Eric Boullier says their rivals cannot be underestimated given seventh to 11th in FP2 on Friday was covered by just over three-tenths, with Alonso and Vandoorne in the mix with Renault, Force India, Toro Rosso and Haas.
"We completed our programme with both cars, which included longer runs at the end of the day and has presented us with useful data in more representative conditions from the upgrades we have brought here.
"Qualifying is all-important tomorrow to decide our grid slots, and we’re under no illusion about the strength of our competition.
"We saw today that the midfield pack is very tight, so positions can be won or lost by the smallest of margins. We have work to do overnight to ensure we give ourselves the best opportunity for Sunday’s race, but we will surely put up a fight here tomorrowin front of our Bahraini friends and colleagues."